2010-12-08 07:13:42 -07:00
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/*
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* CPU frequency scaling for u8500
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* Inspired by linux/arch/arm/mach-davinci/cpufreq.c
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*
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* Copyright (C) STMicroelectronics 2009
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* Copyright (C) ST-Ericsson SA 2010
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*
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* License Terms: GNU General Public License v2
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*
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* Author: Sundar Iyer <sundar.iyer@stericsson.com>
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* Author: Martin Persson <martin.persson@stericsson.com>
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* Author: Jonas Aaberg <jonas.aberg@stericsson.com>
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*
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*/
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#include <linux/platform_device.h>
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#include <linux/kernel.h>
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#include <linux/cpufreq.h>
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#include <linux/delay.h>
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2011-05-15 14:53:56 -06:00
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#include <linux/mfd/db8500-prcmu.h>
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2010-12-08 07:13:42 -07:00
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#include <mach/hardware.h>
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#define DRIVER_NAME "cpufreq-u8500"
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#define CPUFREQ_NAME "u8500"
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static struct device *dev;
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static struct cpufreq_frequency_table freq_table[] = {
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[0] = {
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.index = 0,
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.frequency = 200000,
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},
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[1] = {
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.index = 1,
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.frequency = 300000,
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},
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[2] = {
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.index = 2,
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.frequency = 600000,
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},
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[3] = {
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/* Used for CPU_OPP_MAX, if available */
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.index = 3,
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.frequency = CPUFREQ_TABLE_END,
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},
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[4] = {
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.index = 4,
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.frequency = CPUFREQ_TABLE_END,
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},
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};
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static enum prcmu_cpu_opp index2opp[] = {
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CPU_OPP_EXT_CLK,
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CPU_OPP_50,
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CPU_OPP_100,
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CPU_OPP_MAX
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};
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static int u8500_cpufreq_verify_speed(struct cpufreq_policy *policy)
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{
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return cpufreq_frequency_table_verify(policy, freq_table);
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}
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static int u8500_cpufreq_target(struct cpufreq_policy *policy,
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unsigned int target_freq,
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unsigned int relation)
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{
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struct cpufreq_freqs freqs;
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unsigned int index;
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int ret = 0;
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/*
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* Ensure desired rate is within allowed range. Some govenors
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* (ondemand) will just pass target_freq=0 to get the minimum.
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*/
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if (target_freq < policy->cpuinfo.min_freq)
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target_freq = policy->cpuinfo.min_freq;
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if (target_freq > policy->cpuinfo.max_freq)
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target_freq = policy->cpuinfo.max_freq;
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ret = cpufreq_frequency_table_target(policy, freq_table,
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target_freq, relation, &index);
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if (ret < 0) {
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dev_err(dev, "Could not look up next frequency\n");
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return ret;
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}
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freqs.old = policy->cur;
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freqs.new = freq_table[index].frequency;
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freqs.cpu = policy->cpu;
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if (freqs.old == freqs.new) {
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dev_dbg(dev, "Current and target frequencies are equal\n");
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return 0;
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}
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dev_dbg(dev, "transition: %u --> %u\n", freqs.old, freqs.new);
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cpufreq_notify_transition(&freqs, CPUFREQ_PRECHANGE);
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ret = prcmu_set_cpu_opp(index2opp[index]);
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if (ret < 0) {
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dev_err(dev, "Failed to set OPP level\n");
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return ret;
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}
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cpufreq_notify_transition(&freqs, CPUFREQ_POSTCHANGE);
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return ret;
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}
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static unsigned int u8500_cpufreq_getspeed(unsigned int cpu)
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{
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int i;
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for (i = 0; prcmu_get_cpu_opp() != index2opp[i]; i++)
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;
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return freq_table[i].frequency;
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}
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static int __cpuinit u8500_cpu_init(struct cpufreq_policy *policy)
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{
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int res;
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BUILD_BUG_ON(ARRAY_SIZE(index2opp) + 1 != ARRAY_SIZE(freq_table));
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if (cpu_is_u8500v2()) {
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freq_table[1].frequency = 400000;
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freq_table[2].frequency = 800000;
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if (prcmu_has_arm_maxopp())
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freq_table[3].frequency = 1000000;
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}
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/* get policy fields based on the table */
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res = cpufreq_frequency_table_cpuinfo(policy, freq_table);
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if (!res)
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cpufreq_frequency_table_get_attr(freq_table, policy->cpu);
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else {
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dev_err(dev, "u8500-cpufreq : Failed to read policy table\n");
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return res;
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}
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policy->min = policy->cpuinfo.min_freq;
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policy->max = policy->cpuinfo.max_freq;
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policy->cur = u8500_cpufreq_getspeed(policy->cpu);
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policy->governor = CPUFREQ_DEFAULT_GOVERNOR;
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/*
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* FIXME : Need to take time measurement across the target()
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* function with no/some/all drivers in the notification
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* list.
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*/
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policy->cpuinfo.transition_latency = 200 * 1000; /* in ns */
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/* policy sharing between dual CPUs */
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cpumask_copy(policy->cpus, &cpu_present_map);
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policy->shared_type = CPUFREQ_SHARED_TYPE_ALL;
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return res;
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}
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static struct freq_attr *u8500_cpufreq_attr[] = {
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&cpufreq_freq_attr_scaling_available_freqs,
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NULL,
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};
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static int u8500_cpu_exit(struct cpufreq_policy *policy)
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{
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cpufreq_frequency_table_put_attr(policy->cpu);
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return 0;
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}
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static struct cpufreq_driver u8500_driver = {
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.owner = THIS_MODULE,
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.flags = CPUFREQ_STICKY,
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.verify = u8500_cpufreq_verify_speed,
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.target = u8500_cpufreq_target,
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.get = u8500_cpufreq_getspeed,
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.init = u8500_cpu_init,
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.exit = u8500_cpu_exit,
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.name = CPUFREQ_NAME,
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.attr = u8500_cpufreq_attr,
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};
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static int __init u8500_cpufreq_probe(struct platform_device *pdev)
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{
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dev = &pdev->dev;
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return cpufreq_register_driver(&u8500_driver);
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}
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static int __exit u8500_cpufreq_remove(struct platform_device *pdev)
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{
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return cpufreq_unregister_driver(&u8500_driver);
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}
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static struct platform_driver u8500_cpufreq_driver = {
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.driver = {
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.name = DRIVER_NAME,
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.owner = THIS_MODULE,
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},
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.remove = __exit_p(u8500_cpufreq_remove),
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};
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static int __init u8500_cpufreq_init(void)
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{
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return platform_driver_probe(&u8500_cpufreq_driver,
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&u8500_cpufreq_probe);
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}
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device_initcall(u8500_cpufreq_init);
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